On this page
- What is a full strip-down boiler service?
- How does it compare with a standard or intermediate service?
- What are the signs a boiler needs a strip-down service?
- What happens during a full strip-down service?
- Is a strip-down worth it on an older boiler?
- When is the best time to book one?
- Booking a full strip-down service in Stoke-on-Trent
- Frequently asked questions
Quick answer
A full strip-down boiler service goes further than a standard annual service: the engineer removes and cleans the burner, heat exchanger, electrodes and fan, and replaces disturbed seals. It is often recommended every five to eight years, depending on the boiler and manufacturer guidance, or sooner if combustion readings or symptoms suggest a build-up inside.
Key takeaways
- A strip-down cleans the combustion side that a standard service only inspects.
- Intervals are often five to eight years, depending on make and guidance.
- Poor flue gas readings and rough ignition are common signs it is due.
- It does not replace the annual service; it adds to it periodically.
Most boilers get by year to year on a standard service. But the parts where gas actually burns, the burner and the heat exchanger, gradually collect deposits that a standard visit can check but not properly clean. That is what a full strip-down service is for.
What is a full strip-down boiler service?
A full strip-down service is a deep clean of the boiler's combustion side. The engineer isolates the boiler, removes the burner assembly, cleans the heat exchanger, burner, electrodes and fan, checks and replaces seals that have been disturbed, then reassembles, recommissions and tests it with a flue gas analyser.
A standard service confirms that the boiler is burning safely and efficiently. It includes a visual inspection, combustion analysis, gas pressure checks, safety device checks and cleaning of accessible parts such as the condensate trap. A strip-down goes behind the panels a standard service leaves in place.
Deposits build up for ordinary reasons. The fan draws in household dust and fluff with the combustion air, condensing boilers keep their heat exchangers wet with slightly acidic condensate, and small amounts of corrosion and debris settle where the engineer cannot reach without dismantling the burner. Over several years that build-up can affect how cleanly the boiler burns and how reliably it lights.
How does it compare with a standard or intermediate service?
The three levels differ in how far into the boiler the engineer goes. A standard service is the annual safety and performance check. An intermediate service adds cleaning of more internal components. A full strip-down dismantles the combustion side completely for cleaning and inspection.
| Service level | Typical interval | What it adds | Price |
|---|---|---|---|
| Standard | Every year | Safety checks, combustion analysis, accessible parts cleaned | £90 |
| Intermediate | Often every 3 years once a boiler is over 3 years old | Further internal cleaning and inspection | £124.99 |
| Full strip-down | Often every 5 to 8 years | Burner and heat exchanger removed and cleaned, seals renewed | £225 |
Intervals vary by make and model, so the manufacturer's service instructions take priority. The checks on the standard service are listed in our boiler service checklist.
What are the signs a boiler needs a strip-down service?
The clearest sign is flue gas readings that are drifting in the wrong direction despite the boiler being set up correctly. Other signs include rough or delayed ignition, a burner that looks dirty on inspection, debris in the combustion chamber, and a boiler that has gone many years without anything more than a basic check.
- Combustion readings on the analyser creeping up year on year.
- Noisy, harsh or delayed lighting.
- Visible debris, corrosion or deposits on the heat exchanger.
- Unknown service history, for example after moving house.
- A boiler that has sat unused for a long time, or where insects or debris may have got into the flue.
To see what the job involves in practice, read our report on a full strip-down service in Sneyd Green in Stoke-on-Trent. Flue gas readings are explained in what flue gas analysis is and why it matters.
What happens during a full strip-down service?
The engineer isolates gas and power, removes the casing and sealed chamber cover, and takes out the burner and fan. They clean the burner and heat exchanger, inspect electrodes, renew seals disturbed during the work, then reassemble and check gas tightness and combustion before signing it off.
- Isolate the gas and electrical supply and allow the boiler to cool.
- Remove the burner door or assembly, fan and electrodes.
- Clean the heat exchanger, burner and fan of deposits and debris.
- Inspect electrodes for wear and correct gap; clean or replace as needed.
- Renew seals and gaskets that have been disturbed, as manufacturers generally require.
- Reassemble, test for gas tightness and carry out full combustion analysis.
- Record the work in the Benchmark service record.
Because the job goes much deeper than a standard service, allow a longer appointment. The engineer should tell you before starting if they expect any parts beyond routine seals to be needed.
This is engineer-only work. A strip-down involves breaking and remaking gas seals inside the combustion chamber. Never remove the boiler casing yourself, and only allow a Gas Safe registered engineer to carry it out.
Is a strip-down worth it on an older boiler?
Often, yes. A deep clean can restore clean combustion and quiet ignition, and it gives the engineer a proper look at parts that are otherwise hidden. On an older boiler it also answers an important question: whether the heat exchanger and burner are in good enough shape to keep going.
If the strip-down reveals heavy corrosion or parts at the end of their life, the engineer should tell you plainly. We discuss that decision further in is it worth servicing an old boiler.
When is the best time to book one?
Summer is the easiest time. The heating is off, engineers have more availability than in autumn, and if the strip-down turns up a part that needs ordering, there is time to get it before the weather turns. A strip-down can also take the place of your standard service in the year it is done.
Booking a full strip-down service in Stoke-on-Trent
Our full strip-down service is £225, alongside our standard boiler service in Stoke-on-Trent at £90 and intermediate service at £124.99. If you are unsure which level your boiler needs, the engineer can advise from its age, history and readings.
We also cover boiler service in Endon and boiler service in Blythe Bridge. Call 07896 677083 to book.
Frequently asked questions
Does a full strip-down service replace the annual service?
In the year it is carried out, a full strip-down includes everything a standard service covers, so you would not normally need both. It does not replace the annual service in other years. Most boilers still need a standard service every year, with a strip-down added periodically.
Will a strip-down service fix a faulty boiler?
It can resolve problems caused by dirt and deposits, such as poor combustion or rough ignition. It will not fix a failed component such as a pump, diverter valve or printed circuit board. If a fault is suspected, a repair visit to diagnose it is usually the right first step.
Does my boiler guarantee require a strip-down service?
Most guarantees require an annual service carried out to the manufacturer's instructions by a Gas Safe registered engineer. Some manufacturers specify deeper checks at certain intervals. Check your guarantee paperwork and the service section of the manual, or ask the engineer to check the requirements for your model.
Sources and further reading
Gasmaster Plumbing & Heating has served Stoke-on-Trent since 2005. Every article is written by our Gas Safe registered engineers (reg. 220932) from day to day work on boilers, heating and gas appliances across Staffordshire, Cheshire and Derbyshire.
